Aaron Smith reporting on massive profits Airlines raked in from baggage fees, lists out how the carriers became profitable again:

Carriers responded by cutting the number of flights they offered, slashing those with the fewest passengers. They packed the airplanes full so they wouldn’t lose money on empty seats. And they added fees for services that once came for free, like checked baggage and in-flight food, to boost income.

All of the above is an example of what not to do — all these things make traveling in a plane suck.